Low Voltage Transformers

Low voltage lighting is made possible by the use of low voltage transformers. Sometimes the transformer is built right into the fixture itself, and other times you need to use an external power supply. A lighting transformer literally transforms the standard line voltage in your home or business (120 or 277 volts) to a lower voltage (12 or 24 volts). This lets you safely supply power to popular low voltage lighting systems like recessed can lights, pendant lights, puck lights and outdoor light fixtures.

Low Voltage Transformer Applications & Features

Low voltage lighting systems require less voltage to operate than the typical line voltage supplies. If your wall receptacle outputs 120 volts, that's far more than your 12 or 24 volt light fixture will need. Low voltage transformers step down the voltage to match your light fixture requirements. Without these converters, the electricity coming from your wall receptacle would be far too powerful to operate your low voltage lights and would burn them out.

Electronic vs. Magnetic Transformers

Electronic transformers are smaller in size and provide a maximum of 300 watts of power which makes them a good choice for regulating voltage in smaller lighting applications like kitchens, bathrooms or entertainment rooms. Since magnetic transformers are generally larger and can provide up to 1200 watts of power, they are often ideal for big projects like extensive outdoor landscape lighting. Both types of low voltage transformers have models that can be hard-wired or plugged directly into an outlet and offer single circuit and multi circuit capabilities.

Choosing the Right Low Voltage Transformer

Electronic? Magnetic? Multi-tap? Multi-circuit? Universal? With all of the choices available, sometimes choosing the right low voltage lighting transformer can seem like a daunting task. For an easy 4-step guide to figuring out exactly what kind of transformer you need, see How to Choose a Low Voltage Transformer in 4 Steps.

Wiring Your Low Voltage Transformer

The best resource for electrical wiring is a licensed electrician, but with the right tools and information, it is possible for a homeowner to wire their own low voltage transformer. Make sure that the input wires of the low voltage transformer are connected to the power line using wire nuts, and that the output wires are connected to the low-voltage light source using wire "terminal blocks" of appropriate size (for solid contact). Low voltage halogen or xenon lighting systems carry relatively large currents so all of the connections must be very tight to prevent arcing (a possible fire hazard) within those connections. That's why we recommend that you use terminal blocks. If a low voltage transformer is equipped with wires, then you will usually find that the thicker wires are on the low voltage side and the thinner wires are on the line voltage side.

Troubleshooting Low Voltage Lighting Transformers

Here are a few simple things to look for when you suspect that your transformer isn't working correctly:

Please make certain that the input wires (primary side) of the low voltage transformer are connected to the power line (120 volts or 277 volts) and that the output wires (secondary side) of the low voltage transformer are connected to the low voltage light source (12 volts or 24 volts). Most failures occur as a result of reverse or improper wiring in small electric transformers.

Check the filament (the tiny string-like wire inside the lamp) to see if it is burned out. (Remember the glass envelope of many halogen light bulbs should not be touched by bare hands because the natural oil from your hands will cause the lamp to burn out prematurely.)

Check the connections of the lamp with the socket by moving the lamp inside the lamp holder.

Check the voltage with a voltmeter. (Since most voltmeters give misleading readings when applied to high-frequency currents, the voltage on an electronic low voltage transformer can be measured only by using a "true RMS" voltmeter with a sufficient range.)